Exhaust Gas Recirculation (EGR) Valve
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
The EGR valve is a variable position valve that controls the amount of exhaust that enters the intake manifold. The PCM controls the EGR valve which operates between 0 and 100% duty cycles.
The EGR valve operation can be monitored by viewing the EGR valve position PID. The EGR valve position sensor is integral to the EGR valve.